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Demma MJ, Hohn MJ, Sun A, Mapelli C, Hall B, Walji A, O'Neil J. Inhibition of Myc transcriptional activity by a mini-protein based upon Mxd1. FEBS Lett 2020; 594:1467-1476. [PMID: 32053209 DOI: 10.1002/1873-3468.13759] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/07/2020] [Accepted: 02/10/2020] [Indexed: 12/13/2022]
Abstract
Myc, a transcription factor with oncogenic activity, is upregulated by amplification, translocation, and mutation of the cellular pathways that regulate its stability. Inhibition of the Myc oncogene by various modalities has had limited success. One Myc inhibitor, Omomyc, has limited cellular and in vivo activity. Here, we report a mini-protein, referred to as Mad, which is derived from the cellular Myc antagonist Mxd1. Mad localizes to the nucleus in cells and is 10-fold more potent than Omomyc in inhibiting Myc-driven cell proliferation. Similar to Mxd1, Mad also interacts with Max, the binding partner of Myc, and with the nucleolar upstream binding factor. Mad binds to E-Box DNA in the promoters of Myc target genes and represses Myc-mediated transcription to a greater extent than Omomyc. Overall, Mad appears to be more potent than Omomyc both in vitro and in cells.
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Affiliation(s)
- Mark J Demma
- Oncology Discovery, Merck & Co., Inc., Boston, MA, USA
| | - Michael J Hohn
- Biologics Process R&D, Merck & Co., Inc., Kenilworth, NJ, USA
| | - Angie Sun
- Protein Science, Merck & Co., Inc., Boston, MA, USA
| | | | - Brian Hall
- Protein Science, Merck & Co., Inc., Boston, MA, USA
| | - Abbas Walji
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, NJ, USA
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Brown ZZ, Mapelli C, Farasat I, Shoultz AV, Johnson SA, Orvieto F, Santoprete A, Bianchi E, McCracken AB, Chen K, Zhu X, Demma MJ, Lacey BM, Canada KA, Garbaccio RM, O'Neil J, Walji A. Multiple Synthetic Routes to the Mini-Protein Omomyc and Coiled-Coil Domain Truncations. J Org Chem 2019; 85:1466-1475. [PMID: 31660743 DOI: 10.1021/acs.joc.9b02467] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Myc transcription factor represents an "undruggable" target of high biological interest due to its central role in various cancers. An abbreviated form of the c-Myc protein, called Omomyc, consists of the Myc DNA-binding domain and a coiled-coil region to facilitate dimerization of the 90 amino acid polypeptide. Here we present our results to evaluate the synthesis of Omomyc using three complementary strategies: linear Fmoc solid-phase peptide synthesis (SPPS) using several advancements for difficult sequences, native chemical ligation from smaller peptide fragments, and a high-throughput bacterial expression and assay platform for rapid mutagenesis. This multifaceted approach allowed access to up to gram quantities of the mini-protein and permitted in vitro and in vivo SAR exploration of this modality. DNA-binding results and cellular activity confirm that Omomyc and analogues presented here, are potent binders of the E-box DNA engaged by Myc for transcriptional activation and that this 90-amino acid mini-protein is cell permeable and can inhibit proliferation of Myc-dependent cell lines. We also present additional results on covalent homodimerization through disulfide formation of the full-length mini-protein and show the coiled-coil region can be truncated while preserving both DNA binding and cellular activity. Altogether, our results highlight the ability of advanced peptide synthesis to achieve SAR tractability in a challenging synthetic modality.
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Affiliation(s)
- Zachary Z Brown
- Discovery Chemistry , Merck & Co., Inc. , 2000 Galloping Hill Road , Kenilworth , New Jersey 07033 , United States
| | - Claudio Mapelli
- Discovery Chemistry , Merck & Co., Inc. , 2000 Galloping Hill Road , Kenilworth , New Jersey 07033 , United States
| | - Iman Farasat
- Protein Engineering , Merck & Co., Inc. , 126 East Lincoln Avenue , Rahway , New Jersey 07065 , United States
| | - Alycia V Shoultz
- Protein Engineering , Merck & Co., Inc. , 126 East Lincoln Avenue , Rahway , New Jersey 07065 , United States
| | - Scott A Johnson
- Discovery Chemistry , Merck & Co. , 33 Avenue Louis Pasteur , Boston , Massachusetts 02115 , United States
| | - Federica Orvieto
- Peptide Chemistry , IRBM, SpA , Via Pontina km 30 600 , 00071 Pomezia (RM) , Italy
| | - Alessia Santoprete
- Peptide Chemistry , IRBM, SpA , Via Pontina km 30 600 , 00071 Pomezia (RM) , Italy
| | - Elisabetta Bianchi
- Peptide Chemistry , IRBM, SpA , Via Pontina km 30 600 , 00071 Pomezia (RM) , Italy
| | - Amy Bittner McCracken
- Discovery Chemistry , Merck & Co., Inc. , 2000 Galloping Hill Road , Kenilworth , New Jersey 07033 , United States
| | - Kuanchang Chen
- Discovery Chemistry , Merck & Co., Inc. , 2000 Galloping Hill Road , Kenilworth , New Jersey 07033 , United States
| | - Xiaohong Zhu
- Discovery Chemistry , Merck & Co., Inc. , 2000 Galloping Hill Road , Kenilworth , New Jersey 07033 , United States
| | - Mark J Demma
- Oncology Discovery , Merck & Co., Inc. 33 Avenue Louis Pasteur , Boston , Massachusetts 02115 , United States
| | - Brian M Lacey
- Pharmacology , Merck & Co., Inc. , 33 Avenue Louis Pasteur , Boston , Massachusetts 02115 , United States
| | - Keith A Canada
- Protein Engineering , Merck & Co., Inc. , 126 East Lincoln Avenue , Rahway , New Jersey 07065 , United States
| | - Robert M Garbaccio
- Discovery Chemistry , Merck & Co., Inc. , 2000 Galloping Hill Road , Kenilworth , New Jersey 07033 , United States
| | - Jennifer O'Neil
- Oncology Discovery , Merck & Co., Inc. 33 Avenue Louis Pasteur , Boston , Massachusetts 02115 , United States
| | - Abbas Walji
- Discovery Chemistry , Merck & Co., Inc. , 2000 Galloping Hill Road , Kenilworth , New Jersey 07033 , United States
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Demma MJ, Wong S, Maxwell E, Dasmahapatra B. CP-31398 Restores DNA-binding Activity to Mutant p53 in Vitro but Does Not Affect p53 Homologs p63 and p73. J Biol Chem 2004; 279:45887-96. [PMID: 15308639 DOI: 10.1074/jbc.m401854200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The p53 protein plays a major role in the maintenance of genome stability in mammalian cells. Mutations of p53 occur in over 50% of all cancers and are indicative of highly aggressive cancers that are hard to treat. Recently, there has been a high degree of interest in therapeutic approaches to restore growth suppression functions to mutant p53. Several compounds have been reported to restore wild type function to mutant p53. One such compound, CP-31398, has been shown effective in vivo, but questions have arisen to whether it actually affects p53. Here we show that mutant p53, isolated from cells treated with CP-31398, is capable of binding to p53 response elements in vitro. We also show the compound restores DNA-binding activity to mutant p53 in cells as determined by a chromatin immunoprecipitation assay. In addition, using purified p53 core domain from two different hotspot mutants (R273H and R249S), we show that CP-31398 can restore DNA-binding activity in a dose-dependent manner. Using a quantitative DNA binding assay, we also show that CP-31398 increases significantly the amount of mutant p53 that binds to cognate DNA (B(max)) and its affinity (K(d)) for DNA. The compound, however, does not affect the affinity (K(d) value) of wild type p53 for DNA and only increases B(max) slightly. In a similar assay PRIMA1 does not have any effect on p53 core DNA-binding activity. We also show that CP-31398 had no effect on the DNA-binding activity of p53 homologs p63 and p73.
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Affiliation(s)
- Mark J Demma
- Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA
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